The eighteenth law is Precision, which states: The interface will allow the users to perform a task exactly.
Users want to know that when they perform a task, it will be done accurately and the results will be correct.
Technology Considerations and Implications
Precision will go awry for three reasons:
- There are errors in the underlying code.
- The user and the computer have different expectations of the definition of a task or its outcome.
- There are errors during the interaction, such as speech recognition errors that lessen precision.
The first item—errors in the underlying code—is not directly related to the interface; however, the second and third issues are related. They must be addressed during the design process to minimize their occurrence and the negative effect on precision.